Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Nat Commun. 2012;3:1170. doi: 10.1038/ncomms2183.

Carrier multiplication in semiconductor nanocrystals detected by energy transfer to organic dye molecules.

Author information

  • 1National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China.

Abstract

Carrier multiplication describes an interesting optical phenomenon in semiconductors whereby more than one electron-hole pair, or exciton, can be simultaneously generated upon absorption of a single high-energy photon. So far, it has been highly debated whether the carrier multiplication efficiency is enhanced in semiconductor nanocrystals as compared with their bulk counterpart. The controversy arises from the fact that the ultrafast optical methods currently used need to correctly account for the false contribution of charged excitons to the carrier multiplication signals. Here we show that this charged exciton issue can be resolved in an energy transfer system, where biexcitons generated in the donor nanocrystals are transferred to the acceptor dyes, leading to an enhanced fluorescence from the latter. With the biexciton Auger and energy transfer lifetime measurements, an average carrier multiplication efficiency of ~17.1% can be roughly estimated in CdSe nanocrystals when the excitation photon energy is ~2.46 times of their energy gap.

PMID:
23132020
[PubMed]
PMCID:
PMC3493642
Free PMC Article

Images from this publication.See all images (5)Free text

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for Nature Publishing Group Icon for PubMed Central
    Loading ...
    Write to the Help Desk